How hot is the wire: Optical, electrical, and combined methods to determine filament temperature

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Abstract

The filament temperature T is a key parameter in hotwire-assisted chemical vapor deposition (HWCVD). Three common methods for the in-situ determination of T are based on the measurement of electrical resistance, electrical power, or intensity of thermal radiation at one or more wavelengths λ. This work discusses the errors due to assumptions in these methods, primarily when an assumed resistivity ρ(T) or spectral emittance εs(λ,T) does not match the sample. Further, a method is introduced to find the temperature of a filament behind a viewport with unknown transmittance, and without the need to have references for ρ(T) or εs(λ,T). This method combines multiple thermal radiation spectra at varied radiating power and assumes that εs(λ,T) is independent of T within the resulting variation in T. The combined optical-electrical method is within 30 K in agreement with pyrometry around 2000 K for the real-life filament, and within 20 K of the true T when applied to simulated data of a W filament for which T is known.

Original languageEnglish
Pages (from-to)22-32
Number of pages11
JournalThin solid films
Volume674
DOIs
Publication statusPublished - 31 Mar 2019

Fingerprint

Heat radiation
filaments
wire
Wire
optics
Pyrometry
Acoustic impedance
thermal radiation
Chemical vapor deposition
Wavelength
Temperature
temperature
radiation spectra
electrical resistance
emittance
temperature measurement
transmittance
vapor deposition
electrical resistivity
wavelengths

Keywords

  • Emittance
  • Filament temperature
  • Hot-wire assisted chemical vapor deposition
  • Planck's law
  • Pyrometry
  • Radiation thermometry
  • Resistance thermometry
  • Resistivity

Cite this

@article{98530ec145d94d8cb9696e45c0068770,
title = "How hot is the wire: Optical, electrical, and combined methods to determine filament temperature",
abstract = "The filament temperature T is a key parameter in hotwire-assisted chemical vapor deposition (HWCVD). Three common methods for the in-situ determination of T are based on the measurement of electrical resistance, electrical power, or intensity of thermal radiation at one or more wavelengths λ. This work discusses the errors due to assumptions in these methods, primarily when an assumed resistivity ρ(T) or spectral emittance εs(λ,T) does not match the sample. Further, a method is introduced to find the temperature of a filament behind a viewport with unknown transmittance, and without the need to have references for ρ(T) or εs(λ,T). This method combines multiple thermal radiation spectra at varied radiating power and assumes that εs(λ,T) is independent of T within the resulting variation in T. The combined optical-electrical method is within 30 K in agreement with pyrometry around 2000 K for the real-life filament, and within 20 K of the true T when applied to simulated data of a W filament for which T is known.",
keywords = "Emittance, Filament temperature, Hot-wire assisted chemical vapor deposition, Planck's law, Pyrometry, Radiation thermometry, Resistance thermometry, Resistivity",
author = "Onnink, {Arnoud J.} and Jurriaan Schmitz and Kovalgin, {Alexey Y.}",
year = "2019",
month = "3",
day = "31",
doi = "10.1016/j.tsf.2019.02.003",
language = "English",
volume = "674",
pages = "22--32",
journal = "Thin solid films",
issn = "0040-6090",
publisher = "Elsevier",

}

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T1 - How hot is the wire

T2 - Optical, electrical, and combined methods to determine filament temperature

AU - Onnink, Arnoud J.

AU - Schmitz, Jurriaan

AU - Kovalgin, Alexey Y.

PY - 2019/3/31

Y1 - 2019/3/31

N2 - The filament temperature T is a key parameter in hotwire-assisted chemical vapor deposition (HWCVD). Three common methods for the in-situ determination of T are based on the measurement of electrical resistance, electrical power, or intensity of thermal radiation at one or more wavelengths λ. This work discusses the errors due to assumptions in these methods, primarily when an assumed resistivity ρ(T) or spectral emittance εs(λ,T) does not match the sample. Further, a method is introduced to find the temperature of a filament behind a viewport with unknown transmittance, and without the need to have references for ρ(T) or εs(λ,T). This method combines multiple thermal radiation spectra at varied radiating power and assumes that εs(λ,T) is independent of T within the resulting variation in T. The combined optical-electrical method is within 30 K in agreement with pyrometry around 2000 K for the real-life filament, and within 20 K of the true T when applied to simulated data of a W filament for which T is known.

AB - The filament temperature T is a key parameter in hotwire-assisted chemical vapor deposition (HWCVD). Three common methods for the in-situ determination of T are based on the measurement of electrical resistance, electrical power, or intensity of thermal radiation at one or more wavelengths λ. This work discusses the errors due to assumptions in these methods, primarily when an assumed resistivity ρ(T) or spectral emittance εs(λ,T) does not match the sample. Further, a method is introduced to find the temperature of a filament behind a viewport with unknown transmittance, and without the need to have references for ρ(T) or εs(λ,T). This method combines multiple thermal radiation spectra at varied radiating power and assumes that εs(λ,T) is independent of T within the resulting variation in T. The combined optical-electrical method is within 30 K in agreement with pyrometry around 2000 K for the real-life filament, and within 20 K of the true T when applied to simulated data of a W filament for which T is known.

KW - Emittance

KW - Filament temperature

KW - Hot-wire assisted chemical vapor deposition

KW - Planck's law

KW - Pyrometry

KW - Radiation thermometry

KW - Resistance thermometry

KW - Resistivity

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U2 - 10.1016/j.tsf.2019.02.003

DO - 10.1016/j.tsf.2019.02.003

M3 - Article

VL - 674

SP - 22

EP - 32

JO - Thin solid films

JF - Thin solid films

SN - 0040-6090

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